With the development of various electronic and communication industries, portable terminals have been widely used, and to meet users' demands, functions of the portable terminals have been diversified and the portable terminals have become compact and lightweight.
Early products of the portable terminals have superior antenna radiation efficiency by using external antennas, but due to restriction on slimness and high-integration of the portable terminals, embedded antennas are now actively used for the portable terminals.
However, to configure the external or embedded antenna, an antenna pattern separate from an injection-molded product has to be implemented, increasing the cost of the portable terminal. For this reason, recently, an antenna has been implemented by printing an antenna pattern on a Printed Circuit Board (PCB) without cost increase.
FIGS. 1A through 1C illustrate structural diagrams of an embedded antenna of a conventional portable terminal.
FIG. 1A shows a rear side of a portable terminal in which a PCB Embedded Antenna (PEA) is embedded in a fill-cut region 100 on a lower end portion of the portable terminal. FIG. 1B shows a front side of the portable terminal in which PCB-attaching dome sheets 102 and 104 exist. FIG. 1C shows a region 108 in which the PEA and the dome sheets 102 and 104 are coupled and embedded in the PCB. To implement an antenna by printing a pattern in the PCB, a fill-cut region having a predetermined area or larger, that is, a region where there is no pattern and only a dielectric layer exists, in spite of some variation according to frequency bands, is required and any other metal pattern should not exist in that region.
If an effective area of the fill-cut region except for other metal pattern regions is inefficient, antenna resonance may not be generated at a desired frequency or in spite of generation of resonance, the antenna function may not be achieved due to low antenna radiation efficiency. The reduction of the effective area originates from a pattern on the PCB at a lower end of the portable terminal where a key recognizing dome of a keypad is situated.
As shown in FIGS. 1A through 1C, conventionally, PCB-attaching dome sheets exist on an opposite side to a portion for implementing an antenna pattern, and the pattern is implemented to allow a dome to be situated on the PCB for dome key operations, reducing an antenna embedding region and thus making it difficult to implement a PEA.